﻿using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;

namespace MYTech.Data
{
    /// <summary>
    /// 验证码
    /// </summary>
    public class CheckCode
    {
        public Bitmap CheckCodeBitmap
        {
            get { return checkCodeBitmap; }
        }

        public string CheckCodeString
        {
            get { return checkCodeString; }
        }

        private static Bitmap checkCodeBitmap;
        private static string checkCodeString;
        public CheckCode()
        {
            checkCodeString = GenerateCheckCode();
            checkCodeBitmap = CreateCheckCodeImage(checkCodeString);
        }

        /// <summary>
        /// 生成验证码
        /// </summary>
        /// <returns></returns>
        public static string GenerateCheckCode()
        {
            int number;
            char code;
            string checkCode = String.Empty;
            Random random = new Random();
            for (int i = 0; i < 5; i++)
            {
                number = random.Next();
                if (number % 2 == 0)
                    code = (char)('0' + (char)(number % 10));
                else
                    code = (char)('A' + (char)(number % 26));
                checkCode += code.ToString();
            }
            return checkCode;
        }

        /// <summary>
        /// 创建验证码图片
        /// </summary>
        /// <param name="checkCode"></param>
        /// <returns></returns>
        public static Bitmap CreateCheckCodeImage(string checkCode)
        {

            Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 15.5)), 25);
            Graphics g = Graphics.FromImage(image);
            try
            {
                //生成随机生成器
                Random random = new Random();
                //清空图片背景色
                g.Clear(Color.White);
                //画图片的背景噪音线
                for (int i = 0; i < 25; i++)
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);

                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                }
                using (Font font = new Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic)))
                using (System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true))
                {
                    g.DrawString(checkCode, font, brush, 2, 2);
                }
                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);

                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }
                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                return image;
            }
            finally
            {
                g.Dispose();
            }
        }
    }
}